NAND-type flash memory devices have been used for various applications as a nonvolatile semiconductor memory device. A NAND-type flash memory device has a memory cell array for storing data. A memory cell array is composed of a plurality of memory blocks. Each memory block has memory cells arranged in a matrix comprising of a plurality of rows (word line) and a plurality of columns (bit line). Memory cells in each column constitute a NAND string in which two selection transistors have therebetween a plurality of serially-connected memory cells. Memory cells in each row constitute a page.
A NAND-type flash memory device is structured so that a program operation and a read-out operation are performed on the basis of a page unit. Thus, a NAND-type flash memory device is preferable as a memory in which a large amount of music data or video data is read and programmed simultaneously. A NAND-type flash memory device has been widely used as a USB flash memory (portable flash memory providing connection to a USB connector of a computer) for digital audio equipment or a digital still camera for example.
A NAND-type flash memory device is mainly composed of, for example, a memory cell area for storing data, a resistor for an input or output of data to or from outside, and a decoder for a row direction (word line) and a column direction (bit line), respectively. A program operation to a NAND-type flash memory device (data programming or verify-read processing) is performed on the basis of a page unit. A resistor that temporarily stores to-be-programmed data and to-be-read data is externally provided to a NAND flash memory device. In order to program data to a memory cell, the resistor firstly stores therein the data (e.g., 512 byte or 2048 byte) to subsequently program the stored data to the memory cell. The time required for programming the data to the memory cell is about 200 μsec. In order to read-out data of a page which is desired to be read-out from the memory cell, the data of the page is firstly transferred to the resistor to subsequently output the data from the resistor in a serial manner. This read-out operation requires about 25 μsec for transferring the data from the memory cell and is performed with a short cycle of about 50 nsec in which the data is serially transferred from the resistor. When data is erased, a plurality of pages are simultaneously erased by a block erase operation with about 2 msec, which is longer than the time required for the data program and read-out operations.
Music data and image data require a large file capacity. Thus, a device such a NAND-type flash memory device that can be programmed or read-out with a high speed has increasingly been required. This has provided NAND-type flash memory devices having a higher memory cell capacity and a larger writing unit (page) and a larger erasure unit (block).
Japanese Laid-open Publication No. 2003-203493 for example discloses a NAND-type flash memory device having a means for programming and reading data to or from a NAND-type flash memory device with the higher speed. According to this NAND-type flash memory device, so-called multi page program operation, multi page reading operation, and multiple block erasure operation are performed to simultaneously select a plurality of pages to be programmed or read-out and to simultaneously erase a plurality of blocks.